Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal, soybean meal and white flakes

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.     

Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal,soybean meal and white flakes

Abstract

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.     

粪便收集时间和饲料中肉骨粉含量对异育银鲫(Carassius auratus gibelio) 消化率的影响

本研究探讨了通过收集器不同粪便收集时间和饲料中肉骨粉(MBM)含量对异育银鲫干物质、蛋白、能量、磷的表观消化率 (ADC) 影响.不同梯度(0, 20, 40, 60, 80 ,100%)的肉骨粉替代鱼粉(FM) 蛋白配制成六种等氮 (粗蛋白: 410 g/kg) 等能 (总能: 18 kJ/g) 的饲料,通过11周的饲养实验,实验开始后2周开始收集粪便,收集时间分别是:排粪后 1 min, 投喂后4h和16h. 结果表明,干物质、蛋白、能量、磷的消化率明显随粪便收集时间增加而升高(p<0.05),但在高肉骨粉替代饲料中差异不显著(p>0.05). 干物质、蛋白、能量、磷的消化率随饲料中肉骨粉含量的增加呈线性或近线性下降.因此,在消化率测定中应该尽快收集排出的粪便以保证消化率的真实性.消化率是影响肉骨粉利用一个因素.     

Effects of fibre on digestibility and passage time in callithricidae

The effects of fibre in a pelleted diet on food intake, digestibility of crude fibre, dry matter and energy, on passage time and consistency of faeces were studied in 2 species of Callithricidae, Callithrix jacchus and Saguinus fuscicollis. Coarse cellulose, microcellulose, wheat bran and shrimp meal (chitin = crude fibre) were tested in diets containing 2,4 and 6% total crude fibre, respectively. Digestibility and passage time were determined by inclusion of 0.5% Cr2O3 in the diet. Both celluloses had little influence on the digestibility of energy and dry matter. Digestibility of crude fibre was very low. Wheat bran led to evident depression of energy and dry matter digestibility. High digestibility of crude fibre occurred at the higher levels of inclusion in the diet. Shrimp meal was highly digested with little influence on digestibility of energy and dry matter, indicating considerable degradation of chitin. Wheat bran showed a marked effect, while microcellulose had no effect on passage time, consistency and volume of faeces.     

Digestibility by cattle of diets containing dried pig faeces

The apparent digestibility of diets in which dried pig faeces replaced 0, 15, 30 and 45% of hay (diets A, B, C and D, respectively) was compared using four steers in an experiment of 4 × 4 Latin square design.All rations were readily consumed and no undesirable effect on animal health was observed. Each increase in the proportion of pig faeces in the diet reduced the apparent digestibility of the dietary components. The dry matter digestibility of diets A, B, C and D was 57.9, 52.4, 50.0 and 44.5%, respectively. Similar reductions occurred in the apparent digestibility of crude protein, crude fibre, ether extract and nitrogen-free extract.     

Ileal and total tract digestibility and nitrogen utilisation in blue fox (Vulpes lagopus) fed low-protein diets supplemented with DL-methionine and L-histidine

ABSTRACT

To formulate low-protein diets for blue foxes with sufficient amounts of amino acids (AA), AA digestibility and AA requirements of the animals are crucial information. Therefore, a digestibility and nitrogen (N) balance trial was conducted with 20 blue foxes to determine the macronutrient and AA digestibility and N utilisation in low-protein diets supplemented with DL-methionine (Met) and L-histidine (His). In addition, plasma urea and plasma AA were measured. The diets were designated as P24 (control), P20, P20M, P16M and P16MH and contained energy from digestible crude protein (DCP) at 24%, 20% or 16% of total dietary metabolisable energy (ME). The 20% protein level was fed with or without Met and the 16% protein level was fed with Met and with or without His. The apparent total-tract digestibility (ATTD) of crude protein linearly decreased with decreasing dietary protein level. The ATTD of dry matter, organic matter and crude carbohydrates increased when wheat starch was added as a replacement for protein. The apparent ileal digestibility (AID) and ATTD methods were compared to determine the AA digestibility. The decreasing dietary protein supply decreased the ATTD of most of the AA: threonine, tryptophan (Trp), valine, alanine (Ala), aspartic acid (Asp), glutamic acid, glycine (Gly), proline (Pro), serine (Ser) and total AA. The AID of the AA was constant between diets. Diverging AA showed higher or lower digestibility when determined in the AID or ATTD methods. Isoleucine, lysine, Met, Ala and tyrosine showed higher levels of AID. Arginine, His, cysteine (Cys), Trp, Asp, Gly, Pro and Ser showed higher levels of ATTD, which may reflect the net loss of these AA in the large intestine. Met and His supplementation improved the ATTD and AID of the AA in question, respectively, but did not affect the other variables examined. N retention did not differ between diets and renal N excretion decreased with decreasing protein level; thus N utilisation improved. It was concluded that the protein supply and AA composition in low-protein diets with supplemented Met were adequate for adult blue foxes, since the lower protein supply improved N utilisation and did not affect N retention. However, His supplementation failed to reach the designed level and therefore showed no clear results.     

Ileal digestibility of amino acids of cassava, sweet potato, cocoyam and erythrina foliages fed to growing pigs

Ileal digestibility in growing pigs fed starch-based diets with inclusion of four tropical leaves in a meal form was studied in a 5 × 5 Latin square design. Five diets were formulated with only casein as protein source in the basal diet (CAS), and casein plus dry cassava (CA) leaves, casein plus dry sweet potato (SP) leaves, casein plus dry cocoyam (CO) leaves and casein plus erythrina (ER) leaves in the other four diets. All diets contained the same amount of CP (14%), either provided by only CAS or a combination of casein and 250 g of leaf meal per kg of diet in the other diets. Leaves were separated manually from stems, and only the leaf part was used. A protein-free diet was fed during a sixth period in order to estimate the endogenous protein losses and calculate the CP- and amino-acid (AA)-standardized ileal digestibility (SID) values. The values for the foliages were calculated according to the difference method, assuming no interaction between the foliage and the casein. The ileal tract apparent digestibility of CP, organic matter and energy was higher in diet CAS than in the other diets (P < 0.05). The SID of CP and AA was close to 0.950 for casein, whereas the SID of AA was markedly lower in the foliages; the SID of indispensable and dispensable AA was highest in CO (0.500 and 0.352) and lowest in ER (0.170 and 0.195); intermediate values were obtained for SPs (0.367 and 0.349) and CA (0.232 and 0.242) leaves. Accordingly, the SID of lysine was highest (0.538) for CO leaves and lowest (0.126) in ER leaves; intermediate values were measured for CA and SP leaves. These low SID values in foliage meals must be related to the high levels of dietary fibre and the presence of secondary metabolites (tannins). These results suggest that it is only possible to replace a fraction of the conventional protein sources such as soyabean meal by tropical foliages in growing pig diets with a preference for CO leaves.     

Effect of diet with different protein content on rats during gestation: repercussion on pregnancy development and litter size. Preliminary note

Pregnant rats, Wistar strain, were treated from day 11 of gestation with synthetic diets containing different amounts of protein. The Group of rats fed a severely deficient protein diet (4% of casein, 2% of lactalbumin) showed reduced hematocrit, hemoglobin, total protein and an expressive increase of gamma globulins compared with rats treated with normal or elevated protein levels. Weight gain during pregnancy was higher for rats which received a larger amount of protein; on the contrary those that were subjected to malnutrition had no weight gain and bore prematurely with high percent of foetal mortality.     

Multi-block PCA and multi-compartmental study of the metabolic responses to intake of hydrolysed versus intact casein in C57BL/6J mice by NMR-based metabolomics

Recently we showed that exchanging intact casein with extensively hydrolysed casein in Western diets prevented diet-induced obesity in obesity-prone C57BL/6J mice. To gain further insight into the underlying mechanisms for the metabolic alterations induced by intake of hydrolysed casein, we performed an exploratory investigation using proton NMR spectroscopy, multi-block PCA (MBPCA) and a multi-compartment model including analyses of plasma, urine, faeces and tissue samples from mice fed diets with intact or hydrolysed casein and 16 or 32 energy% protein. The MBPCA superscores showed a clear separation between samples from mice fed intact and hydrolysed casein diets, respectively. Block loadings revealed that fecal fat content was higher, and tissue and plasma lipid levels were lower in mice fed hydrolysed casein diets compared with mice fed intact casein. Amino acid metabolism was also altered by dietary protein form, and levels of branched-chain amino acids were higher in faeces and urine and lower in plasma and spleen in mice fed hydrolysed protein. Moreover, hepatic levels of the sulphur-containing metabolites taurine and glutathione were increased in mice fed hydrolysed casein, and hepatic glycogen amount was increased in mice fed hydrolysed casein. In contrast, the levels of glucose and its metabolite lactate were reduced in faeces, liver and plasma. Taken together, NMR-based metabolomic analyses indicated that pathways within lipid, amino acid and carbohydrate metabolism were altered by intake of hydrolysed casein, and that these alterations are likely to be underlying mechanisms for the observed prevention against diet-induced obesity associated with hydrolysed casein intake.     

Nutritional value of the marine invertebrates Anemonia viridis and Haliothis tuberculata and effects on serum cholesterol concentration in ratsopen star

The purpose of this study was to determine the nutritional value of diets with protein from two marine species (Haliotis tuberculata and Anemonia viridis) as compared to a high-quality protein reference based on casein or casein supplemented with olive oil. We also investigated the effects of these diets on serum lipid levels. Male rats were fed these diets for 23 days. Protein quality indicators (true digestibility, net protein utilization, biological value) were similar to those obtained for casein-based feeds except for lower true digestibility and net protein utilization values for the Anemonia viridis feed. HDL-cholesterol level was significantly higher (p < 0.05) in the groups fed marine species or casein supplemented with olive oil than in the casein group. Total-cholesterol level was higher in the group fed Haliotis tuberculata fed than in the other groups. These results suggest that these marine species are a good protein source, and that they may have positive effects on serum cholesterol level.     

The Effects of Sugar Alcohols on Metabolism of Growing Pigs

In two experiments of 3 × 3 Latin square with growing pigs, the effect was investigated of supplementation of 5 % or 10 % (2.5 % vs. 5 % DM) polyol mixture and 2.5 % or 5 % of xylitol on digestibility of diet, N-balance, blood clinical-chemical parameters and insulin level in serum. Apparent digestibility of crude protein was lower for the diet with 10 % polyol mixture compared to the control. Sugar alcohols were not found in faeces. Arabinitol, mannitol and rhamnitol were excreted in the urine 25–67 %. Little sorbitol and xylitol were found in urine on diets with polyol mixture 5–10 %. On xylitol diets the pigs did not excrete xylitol in urine. Plasma glucose rose in pigs fed xylitol. Blood total protein and albumin decreased in pigs fed polyol mixture. ALAT-activities were higher for xylitol diets than for the controls. Serum insulin tended to increase in pigs fed polyol mixture 10 % one hour after feeding, and in xylitol feeding two hours after feeding; these values were higher with increasing xylitol inclusion in diet.     

Effects of pelleted total mixed rations with different rumen degradable protein on milk yield and composition of Jonica dairy goat

The present study was conducted in order to examine the effects of diets with different ruminal degradable protein sources on the performance of lactating goats fed pelleted total mixed rations (PTMR). Forty multiparous Jonica goats in early-lactation were divided into two equal groups and fed for 135 days the experimental diets. Two types of PTMR were formulated to be isonitrogenous and isocaloric while providing different rumen degradable levels of crude protein: (1) high-degradable protein diet (HD) containing soybean meal, sunflower meal and urea (46% N), and (2) low-degradable protein diet (LD) including only corn gluten meal. Apparent digestibility of the two PTMR was tested using Jonica bucks placed in individual pens and results indicated significant differences (P < 0.05) for crude protein, crude fibre, neutral detergent fibre and acid detergent fibre nutrients’ utilization. In milk performance trial, no significant differences (P > 0.05) were registered in dry matter intake and milk yield. Goats fed LD diet containing corn gluten meal showed the highest milk fat, protein and casein concentration, but not significant differences (P > 0.05) were observed on other milk components and renneting properties. It was concluded that a decrease of rumen degradable protein (RDP) level in PTMR does not negatively influence nutrient utilization and milk production and composition of Jonica dairy goat.     

饲料中土豆蛋白替代鱼粉对虹鳟摄食率、消化率和生长的影响

通过生长试验探讨了饲料中土豆蛋白浓缩物替代鱼粉后对虹鳟摄食率,消化率,生长和饲料利用的影响,对照饲料全部鱼粉为蛋白源,其它饲料分别含土豆蛋白２．２％,５．６％,８．９％和１１．１％,另一饲料含５．６％,土豆蛋白和１．７％蛋氨酸,在１２℃下饲养４周,试验结果表明,随着饲料中土豆蛋白使用比例的增加,虹鳟的摄食率下降,饲料的干物质,蛋白和灰分的表现消化率上升,脂肪的表现消化率无显著影响,当饲料中含５．６     

Effects of caecectomy in the young adult female rat on digestibility of food offered ad libitum and in restricted amounts.

Caecectomized and sham-operated rats were fed a laboratory chow ad libitum and the effects of caecectomy on the digestibility of the food were studied. Compared with sham-operated controls, caecectomized rats showed a decrease in apparent digestibiltiy of organic matter from 77.8 to 73.0%, of crude protein from 83.0 to 79.4%, and of 'carbohydrate' from 74.6 to 69.0%. However, faecal water content increased from 41.6 to 54.8%. 51Cr-labelled EDTA was excreted faster in the faeces after caecectomy. The colon partly adapted to the loss of caecal mucosa by increased length and thus mucosal surface area. In a second concurrent experiment the effect of caecectomy on the apparent digestibility of food during food restriction was studied. Six caecectomized rats, comparable in all respects to those used in the first study, were fed the laboratory chow ad libitum for 3 weeks. They were then fed submaintenance amounts of food to achieve body weight losses of 40--50% and to maintain these low weights for 4 weeks. Finally, they were again fed ad libitum for 3 weeks. During the period of restriction the apparent digestibility of organic matter increased from 72.7 to 75.4%. This was largely due to the increased apparent digestibility of crude protein which rose from 78.4 to 81.9%. Digestibility coefficients returned to control values immediately upon refeeding ad libitum.     

A Mixture of Cod and Scallop Protein Reduces Adiposity and Improves Glucose Tolerance in High-Fat Fed Male C57BL/6J Mice

Low-protein and high-protein diets regulate energy metabolism in animals and humans. To evaluate whether different dietary protein sources modulate energy balance when ingested at average levels obesity-prone male C57BL/6J mice were pair-fed high-fat diets (67 energy percent fat, 18 energy percent sucrose and 15 energy percent protein) with either casein, chicken filet or a mixture of cod and scallop (1∶1 on amino acid content) as protein sources. At equal energy intake, casein and cod/scallop fed mice had lower feed efficiency than chicken fed mice, which translated into reduced adipose tissue masses after seven weeks of feeding. Chicken fed mice had elevated hepatic triglyceride relative to casein and cod/scallop fed mice and elevated 4 h fasted plasma cholesterol concentrations compared to low-fat and casein fed mice. In casein fed mice the reduced adiposity was likely related to the observed three percent lower apparent fat digestibility compared to low-fat, chicken and cod/scallop fed mice. After six weeks of feeding an oral glucose tolerance test revealed that despite their lean phenotype, casein fed mice had reduced glucose tolerance compared to low-fat, chicken and cod/scallop fed mice. In a separate set of mice, effects on metabolism were evaluated by indirect calorimetry before onset of diet-induced obesity. Spontaneous locomotor activity decreased in casein and chicken fed mice when shifting from low-fat to high-fat diets, but cod/scallop feeding tended (P = 0.06) to attenuate this decrease. Moreover, at this shift, energy expenditure decreased in all groups, but was decreased to a greater extent in casein fed than in cod/scallop fed mice, indicating that protein sources regulated energy expenditure differently. In conclusion, protein from different sources modulates energy balance in C57BL/6J mice when given at normal levels. Ingestion of a cod/scallop-mixture prevented diet-induced obesity compared to intake of chicken filet and preserved glucose tolerance compared to casein intake.     

Effects of dehydrated lucerne and soya bean meal on milk production and composition,nutrient digestion,and methane and nitrogen losses in dairy cows receiving two different forages

Dehydrated lucerne is used as a protein source in dairy cow rations, but little is known about the effects of lucerne on greenhouse gas production by animals. Eight Holstein dairy cows (average weight: 582 kg) were used in a replicated 4×4 Latin square design. They received diets based on either maize silage (M) or grass silage (G) (45% of diet on dry matter (DM) basis), with either soya bean meal (15% of diet DM) completed with beet pulp (15% of diet DM) (SP) or dehydrated lucerne (L) (30% of diet DM) as protein sources; MSP, ML, GSP and GL diets were calculated to meet energy requirements for milk production by dairy cows and degradable protein for rumen microbes. Dry matter intake (DMI) did not differ among diets (18.0 kg/day DMI); milk production was higher with SP diets than with L diets (26.0 v. 24.1 kg/day), but milk production did not vary with forage type. Milk fatty-acid (FA) composition was modified by both forage and protein sources: L and G diets resulted in less saturated FA, less linoleic acid, more trans-monounsaturated FA, and more linolenic acid than SP and M diets, respectively. Enteric methane (CH₄) production, measured by the SF₆ tracer method, was higher for G diets than for M diets, but did not differ with protein source. The same effects were observed when CH₄ was expressed per kg milk. Minor effects of diets on rumen fermentation pattern were observed. Manure CH₄ emissions estimated from faecal organic matter were negatively related to diet digestibility and were thus higher for L than SP diets, and higher for M than G diets; the resulting difference in total CH₄ production was small. Owing to diet formulation constraints, N intake was higher for SP than for L diets; interaction between forage type and protein source was significant for N intake. The same statistical effects were found for N in milk. Faecal and urinary N losses were determined from total faeces and urine collection. Faecal N output was lower for M than for G diets but did not differ between protein sources. Urinary N output did not differ between forage types, but was lower for cows fed L diets than for cows fed SP diets, potentially resulting in lower ammonia emissions with L diets. Replacing soya bean meal plus beet pulp with dehydrated lucerne did not change CH₄ production, but resulted in more N in faeces and less N in urine.     

Effects of fibre-degrading enzymes in combination with different fibre sources on ileal and total tract nutrient digestibility and fermentation products in pigs

ABSTRACT

The study was conducted to determine effects of a complex of fibre-degrading enzymes (xylanase, cellulase and β-glucanase) on nutrient digestibility, fibre fermentation and concentrations of short chain fatty acids (SCFA) at different parts of digestive tract in pigs fed different fibre-rich ingredients. A total of 36 barrows fitted with T-cannulas in the distal ileum (initial body weight of 41.1 ± 2.7 kg) were randomly allotted to six dietary treatments with three different high-fibre diets including maize bran (MB), sugar beet pulp (SBP) and soybean hulls (SH) with or without supplementation of fibre-degrading enzymes. Enzyme supplementation improved (p < 0.05) apparent ileal digestibility (AID) of dietary gross energy (GE), crude protein, dry matter (DM), organic matter (OM), total dietary fibre (TDF), neutral detergent fibre (NDF) and apparent total tract digestibility (ATTD) of dietary GE, DM, OM, TDF, insoluble dietary fibre (IDF) when pigs were fed MB, SBP or SH diets. When compared to the SBP and SH diets, the AID of GE, DM, ash, OM and NDF in diet MB was higher (p < 0.05), but the hindgut disappearance and ATTD of nutrients, except for ether extract and crude ash, were lower (p < 0.05). Enzyme supplementation increased acetate and total SCFA concentrations in ileal digesta and faeces of pigs. In conclusion, enzyme addition improved IDF fermentation and SCFA concentration in the whole intestine of pigs, and there was a large variation of digestibility of fibre components among MB, SH and SBP owing to their different fibre composition. Therefore, fibre-degrading enzymes should be applied to fibrous diets to improve efficient production of swine, especially considering low fibre digestibility of fibre-rich ingredients.     

Ileal and total tract nutrient digestibility in blue foxes (Alopex lagopus) fed extruded diets containing different protein sources

This study compared apparent ileal and total tract digestibility of macronutrients and amino acids in blue foxes (Alopex lagopus) fed dry extruded diets. The control diet contained fish meal as the main protein source, while in the other diets 50% of the fish meal protein was replaced by not de-hulled solvent-extracted soybean meal, meat meal or bacterial protein meal. Ileal digestibility was obtained with animals modified with ileorectal anastomosis (IRA method). There were no significant differences in the average digestibility of CP, Lys, Trp, Val, Ala or Glu between IRA modified and intact animals. Average ileal digestibilities of His, Thr, Asp, Cys, Gly, Hyp, Pro, Ser, starch and total carbohydrates (CHO) were significantly lower compared with total tract values. Average ileal digestibility of Arg, Ile, Leu, Met, Phe, Tyr and crude fat was significantly higher than total tract digestibility. Digestibility measured in IRA modified animals showed less variability compared with values from intact animals. There were significant differences among diets in ileal as well as total tract digestibility of orude protein, most amino acids, starch and CHO, and in ileal digestibility of crude fat. Ileal crude protein digestibility of the diets ranged from 81.0-86.4% and total tract digestibility from 82.5-86.4%. Ileal amino acid digestibilities ranged from 70.1 (Asp) to 93.3% (Arg) and total tract values ranged from 72.8 (Cys) to 92.2% (Arg). Both ileal and total tract digestibilities of crude protein and most amino acids were significantly lower for diets containing meat meal or bacterial protein meal compared with the control fish meal-based diet and the diet with soybean meal. Although ileal digestibility may be more accurate than total tract digestibility in estimating the protein and amino acid supply in blue foxes, total tract digestibility may be acceptable because of numerically small differences between ileal and total tract digestibilities for protein and most amino acids. It was further concluded that ileal digestibilities of starch and CHO in the blue fox are lower than corresponding total tract digestibilities.     

Growth performance, digestibility and faecal coliform bacteria in weaned piglets fed a cereal-based diet including either chicory (Cichorium intybus L) or ribwort (Plantago lanceolata L) forage

Twenty-five weaned 35-day-old piglets were used in a 35-day growth experiment to evaluate the effect of inclusion of chicory and ribwort forage in a cereal-based diet on growth performance, feed intake, digestibility and shedding of faecal coliform bacteria. A total of seven experimental diets were formulated, a cereal-based basal diet (B), and six diets with inclusion of 40, 80 and 160 g/kg chicory (C40, C80 and C160) or ribwort (R40, R80 and R160). Piglets had ad libitum access to feed and water throughout the experiment. Three and five weeks post-weaning faeces samples for determination of digestibility were collected once a day for five subsequent days. Additional faeces samples for determination of coliform counts were collected at days 1, 16 and 35 post-weaning. Piglets fed diet R160 had the lowest average daily feed intake (DFI) and daily weight gain (DWG), and differed (P < 0.05) from piglets fed diets B, R40 and R80. There were no differences in DFI and DWG between the chicory diets and diet B. Inclusion of chicory or ribwort had a minor negative impact on the coefficient of total tract apparent digestibility (CTTAD) of dry matter, organic matter and crude protein, whereas inclusion of both chicory and ribwort resulted in higher CTTAD of non-starch polysaccharides and neutral detergent fibre (NDF). The CTTAD of arabinose were higher for diets C160 and R160 than for diet B (P < 0.05), and the CTTAD of uronic acid was higher for diets C40, C80, C160, R80 and R160 than for diet B (P < 0.05). Age affected the CTTAD for all parameters (P < 0.05) except for NDF, with higher values at 5 than at 3 weeks post-weaning. The coliform counts decreased with increasing age (P < 0.05), but was not affected by treatment. The results indicate that inclusion of up to 160 g/kg of chicory do not negatively affect performance, whereas high inclusion of ribwort have a negative impact on feed consumption and consequently on growth rate. Both herbs have a higher digestibility of fibre compared to cereal fibre. Chicory and ribwort are both promising as feedstuffs to weaned piglets, but the low palatability of ribwort limits the inclusion level.     

Optimum dietary crude protein level for finishing Awassi lambs

Awassi is a multi-purpose sheep breed. Awassi lambs being finished are usually offered an 18% crude protein (CP) diet. The growth rate of Awassi lambs is lower than other meat breeds. Therefore, this high content of dietary CP is questionable. The objective of this study was to estimate the optimum CP level for finishing Awassi lambs. Fifty male Awassi lambs (23.0±1.2 kg) were fed five high concentrate isocaloric diets (10 lambs per diet) that contained 10, 12, 14, 16, and 18% CP in a totally mixed diets for 9 weeks using a completely randomized design. Lambs were fed twice daily, and feed offered and feed refusals recorded for each feeding. Individual lamb intakes were calculated using daily feed offered and feed refused averaged over the interval of the experiment. Digestibility estimates were measured by total fecal collection. Lambs fed diets that contained 10, 12, and 14% CP gained less weight than those fed the 16 and 18% CP diets (P<0.05). Dry matter and CP intakes increased (P<0.05) with increasing levels of dietary CP. No difference (P>0.10) was observed in feed-to-gain ratio between diets except for the diet that contained 10% CP (P<0.05) which had a lower ratio. Organic matter and CP digestibility were lowest in lambs fed the 10% CP diet. Results suggest that the optimum CP concentration is 16% and that any increase above this level will not result in any improvement in production.